opencv_test_viz creates windows and waits until user close them,
it is not appropriate for automatic testing

* use new syntax introduced in CMake 2.8.0
* set OPENCV_TEST_DATA_PATH enviroment property

Install symlinks to shared libraries as a part of development package,
not runtime package.

It is default behavior for debian packages.

ContextImpl::currentContext contains a reference to one of the
DeviceInfoImpl objects from:

static std::vector<DeviceInfoImpl> global_devices;

ContextImpl::currentContext is destroyed in the destructor
for the statically defined object __module, and relies on its
DeviceInfoImpl reference to query some hardware features while
being destroyed.

This means that we need to ensure that the global_devices vector is
destroyed affter __module, otherwise ContextImpl::currentContext's
DeviceInfoImpl reference will no longer be valid when __module is
destroyed.

Since these variables are all confined to a single compilation unit,
they will be destruct from bottom to top, so we need to make sure
that __module is the bottom definition so it can be destroyed first.

This bug was triggered by Buildroot autobuilders [1,2], causing this
kind of failures [3,4]:

  [ 14%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/system.cpp.o
  /home/test/autobuild/instance-0/output/build/opencv-2.4.10/modules/core/src/system.cpp: In function '(static initializers for /home/test/autobuild/instance-0/output/build/opencv-2.4.10/modules/core/src/system.cpp)':
  /home/test/autobuild/instance-0/output/build/opencv-2.4.10/modules/core/src/system.cpp:280:10: error: inconsistent operand constraints in an 'asm'
  make[3]: *** [modules/core/CMakeFiles/opencv_core.dir/src/system.cpp.o] Error 1

[1] http://buildroot.org/
[2] http://autobuild.buildroot.org/
[3] http://autobuild.buildroot.org/?reason=opencv-2.4.10
[4] http://autobuild.buildroot.org/results/483/4838285b25d6293a5cf0bb9eadd5040a7c75d766/build-end.logSigned-off-by: Samuel Martin <s.martin49@gmail.com>